DE60317125T2 - Cooling system for an internal combustion engine - Google Patents

Description

BACKGROUND OF THE INVENTION

1. Field of the invention

The Invention relates to a cooling system, for that is designed, an internal combustion engine by circulating a coolant and by effecting a heat exchange between the coolant and to cool the internal combustion engine.

2. Description of the state of the technique

One known cooling system for one water-cooled Internal combustion engine installed in a motor vehicle has a heat sink or radiator grille in a coolant circulation path of the Internal combustion engine is provided to a coolant or cooling water to cool, and a flow valve, that's the flow rate of the coolant, the flows through the heat sink controls. In this type of cooling system changes the temperature of the engine coolant according to the flow rate the coolant, by controlling the opening of the flow valve is controlled.

An example of the control of the flow valve opening is in the example Japanese Patent Laid-Open Publication No. 5-179948 disclosed. Under the disclosed valve opening control, a desired coolant temperature is set based on the engine load and the engine speed. Then, the opening of the flow valve is feedback controlled so that the actual temperature of the engine coolant becomes equal to the set coolant target temperature. With this control, the flow rate of the coolant flowing through the heat sink is controlled, and the temperature of the engine coolant approaches and substantially equalizes the target coolant temperature.

With The known technique described above is the temperature of the refrigerant dependent Regulated by the load condition or the load condition of the internal combustion engine. When the internal combustion engine generate a high level of drive power therefore, the coolant temperature is lowered, about the cooling capacity of the engine cylinder to increase. When the internal combustion engine with low fuel consumption (ie with high fuel efficiency) on the other hand, the coolant temperature is increased to the Increase combustion power of the cylinder. This way will the coolant temperature so regulated that sufficiently high levels of opposite Performances or characteristic values, d. H. high power (output power) and low fuel consumption.

In in the above publication disclosed cooling system is the control of the flow valve opening only based on a difference between the actual Coolant temperature and the desired coolant temperature carried out. Therefore, the cooling system suffers at a low responsiveness when the coolant temperature to the coolant setpoint temperature is regulated. In particular, when an amount of heat that is a cooling loss of the internal combustion engine corresponds to a change the operating state of the internal combustion engine changes, the coolant temperature not with a good responsiveness to the target coolant temperature be managed. Here, the loss of coolant is a quantity of heat, which is withdrawn from the engine and into the coolant is radiated or absorbed by this, while the coolant is the internal combustion engine flows through. When the coolant loss changes as described above, comes It results in a loss of performance, fuel efficiency improvements and the output power is in conflict. A similar problem can be solved in one cooling system arise in which the flow rate a coolant, which flows through a heat sink, from an electric water pump is controlled instead of the flow valve.

SUMMARY OF THE INVENTION

Therefore It is an object of the invention to provide a cooling system for an internal combustion engine create in which the coolant temperature the internal combustion engine with improved responsiveness to the coolant setpoint temperature can be regulated, even if the coolant loss with a change the operating state of the internal combustion engine changes.

In order to achieve the above object, according to one aspect of the invention, there is provided a cooling system for an internal combustion engine having a radiator grille provided in a coolant circulation path of the internal combustion engine and an actuator having a flow rate of the coolant flows through the heat sink controls, wherein the actuator is controlled so that a coolant temperature of the internal combustion engine is substantially equal to a desired coolant temperature, comprising: (a) a computing unit, the cooling loss as an amount of heat, which is withdrawn from the internal combustion engine and the coolant is calculated, based on an operating condition of the internal combustion engine calculated and a required heat sink flow rate on the basis of the cooling loss, the target coolant temperature and a temperature of the coolant flowing through the heat sink, calculated, the required heat sink flow rate represents a quantity of coolant caused by the cooling body must flow so that the coolant temperature is substantially equal to the desired coolant temperature; and (b) a controller that controls the actuator based on the required heat sink flow rate determined by the computing unit.

In the cooling system, which is constructed as described above, calculates the arithmetic unit the amount of heat the cooling loss of the internal combustion engine corresponds, d. H. the amount of heat passing through the coolant is deducted while the coolant flows through the internal combustion engine, on the basis of the operating state of the internal combustion engine. As well becomes the required heat sink flow rate, d. H. the amount of coolant which must flow through the heat sink, so that the coolant setpoint temperature is reached is based on the cooling loss, the coolant set temperature and the temperature of the coolant, which has passed through the heat sink, calculated. The control unit of the system controls the actuator based on the required heatsink flow rate provided by the computational unit was determined. With this control, the flow rate the coolant, which flows through the heat sink, on controlled in a suitable manner, so that the coolant temperature of the internal combustion engine the coolant target temperature is approaching and essentially resembles.

Also when the cooling loss (i.e., the amount of heat, the cooling loss corresponds) with a change the operating state of the internal combustion engine changes, thus becomes the actuator according to the change the cooling loss controlled. Therefore, the coolant temperature of the internal combustion engine with good responsiveness to the Target coolant temperature be managed.

In the cooling system according to the above Aspect of the invention includes the operating state of the internal combustion engine, for calculating the cooling loss is used, a speed of the internal combustion engine and / or a Engine load. In this case, the cooling loss can be done with high accuracy be determined.

Further can in the cooling system described above the control unit has an opening command value based on the required heatsink flow rate provided by the computational unit was determined, and the operating condition of the internal combustion engine calculate, and an opening of the actuator may be in accordance with the opening command value to be controlled.

in the In the above case, the opening command value becomes the base of the required heat sink flow rate, which is obtained from the arithmetic unit, and the operating state of the internal combustion engine determined. When the opening of the actuator is controlled in accordance with the thus-determined opening command value will, is the flow rate the coolant, which flows through the heat sink, on suitable way ge controls, so that the coolant temperature of the engine easily to the coolant setpoint temperature is regulated.

In an embodiment The above aspect of the invention further calculates the arithmetic unit a recorded / radiated heat quantity of a Heat absorption / radiation cycle, the provided in the coolant circulation path is and bypasses the heat sink, and calculates the required heat sink flow rate based on received / radiated heat in addition to Cooling loss, the coolant set temperature and the temperature of the coolant, that has flowed through the heat sink.

at the above arrangement in which the heat receiving / radiating Cycle or cycles, bypass the heat sink, are provided, takes the coolant Heat up or shines off while it by the heat receiving / radiating circuit or circuits flows. The Coolant, the heat has absorbed or radiated flows into the coolant Umwälzweg and flows again by the internal combustion engine.

According to the above described embodiment becomes the required heat sink flow rate based on the amount of heat in the heat recorded receiving / radiating circuit or the circuits or is emitted, in addition for cooling loss, the coolant set temperature and the temperature of the coolant, which has passed through the heat sink, calculated. Then the control unit controls the actuator on the Based on the required heat sink flow rate, which was determined by the arithmetic unit.

Thus, even if the amount of heat absorbed or radiated in the heat receiving / radiating circuit (s) changes, the coolant temperature is smoothly and more accurately controlled to the target coolant temperature without any problem. That is, the degree of over or under control of the coolant temperature can be reduced, and therefore, the target coolant temperature does not have to be lowered in view of the thermal resistance of components constituting the engine. In this document, oversteer refers to a phenomenon in which the coolant temperature exceeds the target coolant temperature after the target level has been reached, and understeer refers to a phenomenon in which the coolant temperature falls below the target coolant temperature after turning on the setpoint level has been lowered. Since the target coolant temperature does not need to be lowered, as described above, friction increases in the engine and automatic transmission due to the otherwise possible lowering of the coolant target temperature - and thus the deterioration of the fuel economy (ie, an increase in fuel consumption) - avoided or suppressed .

In the cooling system described immediately above, the above Heat absorbing / radiating Circuit consisting of a plurality of heat receiving / radiating circuits, and the arithmetic unit can measure the amount of heat absorbed / radiated the heat receiving / radiating circuits, a compound coolant temperature, measured at the merging section and the coolant temperature of the internal combustion engine. Thus, the recorded / radiated heat using the flow rate and the temperature of the coolant in the union section as a parameter which the recorded / radiated heat in the heat affect receiving / radiating circuits, with improved Accuracy can be determined.

In another embodiment of the invention, the arithmetic unit further calculates a quantity of heat, that of a main body of the internal combustion engine is radiated, and calculates the required Heatsink flow rate based on the amount of heat that of the engine body is emitted, in addition for cooling loss, the coolant set temperature and the temperature of the coolant, which has flowed through the heat sink.

It It is assumed that the cooling loss is with a change the heat, the one from the main body of the internal combustion engine is radiated (a lot, below is called "engine body irradiation heat amount"), as well as with a change the operating state of the internal combustion engine changes. According to this embodiment Therefore, the amount of heat, the from the engine body is radiated, calculated, and the calculated amount of heat beats in the calculation of the heat sink flow rate low. Accordingly, too when the engine body radiant heat amount changes, the Coolant temperature Easier and more accurately controlled to the coolant setpoint temperature. This means, the degree of over- or Understeer of the coolant temperature can be reduced, and therefore, the desired coolant temperature must be in In terms of thermal resistance of components that make up the internal combustion engine be lowered. This arrangement allows the avoidance and suppression of Increase in friction in the internal combustion engine and in the automatic transmission due otherwise possible Lowering the coolant set temperature, and thus also the deterioration of fuel economy (i.e. H. an increase of fuel consumption).

In the cooling system described immediately above, the internal combustion engine be installed in a vehicle, and the arithmetic unit can the Engine body radiating heat on the basis of a driving speed of the vehicle and a Calculate the temperature around the vehicle. Thus, the engine body radiant heat amount be determined with improved accuracy by the driving speed the vehicle and / or the ambient temperature as a parameter, which the amount of heat that of the engine body is radiated, influence, be used or become.

BRIEF DESCRIPTION OF THE DRAWING

The and / or other objects, features and advantages of the present invention Invention will become apparent from the following description of embodiments with reference to the accompanying drawing more clearly, in the similar Reference numbers are used to designate like elements and wherein:

1 is a schematic view showing the structure of a cooling system of an internal combustion engine according to a first embodiment of the invention;

2 Fig. 10 is a flowchart showing a control routine for controlling the temperature of the coolant;

3 Fig. 12 is a schematic diagram of a map used to determine the amount of heat corresponding to the cooling loss;

4 is a schematic representation of a map that is used to determine the opening command value;

5 is a schematic diagram showing the structure of a cooling system of an internal combustion engine according to a second embodiment of the invention;

6 Fig. 10 is a flowchart showing a control routine for controlling the temperature of the coolant;

7 is a schematic representation of a map that is used to determine the Strömungsra te of the coolant is used in a merging section, where the heat receiving / radiating circuits that bypass the heat sink, unite into a single path;

8th is a schematic representation of a map that is used to determine the basic amount of heat emitted by an engine body;

9 Fig. 12 is a schematic representation of a map used to determine the ambient temperature correction factor; and

10 Fig. 10 is a flowchart showing a control routine for controlling the temperature of the refrigerant in a refrigeration system according to the third embodiment of the invention;

DETAILED DESCRIPTION OF THE EMBODIMENTS

First embodiment

A first embodiment of the invention will be described with reference to FIG 1 to 4 described in detail.

As in 1 As shown, an essential part of a multi-cylinder engine installed in a vehicle is an engine body 12 including a cylinder block, a cylinder head, and other components. At the engine body 12 is an inlet channel 13 , is introduced through the air in a combustion chamber of the respective cylinder connected. The inlet channel 13 is with an air scrubber 14 and a throttle body 15 fitted. The air scrubber 14 is a filter that contains dust in the air that enters the engine body 12 is introduced, captures and removes. A throttle 16 is rotatable in the throttle body 15 stored, and a throttle motor 17 to control the throttle 16 is effective with the throttle 16 coupled.

An electronic control unit (ECU) 35 controls the throttle motor 17 as described later on the basis of an operation by the driver, with the accelerator pedal 18 is depressed, and other parameters to the throttle 16 to turn. The amount of intake air, which is the amount of air passing through the inlet duct 13 flows, changes according to the throttle opening (ie, the rotation angle of the throttle valve 16 ). In the combustion chamber of each cylinder is a mixture of a fuel and the air passing through the inlet duct 13 is fed, burned. Part of the heat energy generated in the combustion of the air / fuel mixture is converted into power for rotation of a crankshaft 19 converted as output shaft of the internal combustion engine. At the engine body 12 are also an outlet channel 21 , by the combustion gas generated in the combustion chamber, from the internal combustion engine 11 is discharged, connected. Another portion of the thermal energy that is not converted into power may be lost in the form of a frictional loss, and the remainder of the thermal energy is dissipated from various portions of the engine body 12 absorbed. A water cooling cooling system 20 as described below, is provided to prevent the heat thus absorbed from the engine body 12 is absorbed, the engine body 12 overheated.

A water jacket (not shown) serving as a channel for a coolant or cooling water is inside the engine body 12 arranged. A heat sink or grille 22 is via a heat sink channel or grille channel 23 with an inlet 10a and an outlet 10b connected to the water jacket.

A water pump (W / P) 24 is at the inlet 10a attached to the water jacket. The water pump 24 is by means of a pulley, a belt and the like with the crankshaft 19 connected and designed to take advantage of the rotation of the crankshaft 19 arising from an operation of the internal combustion engine 11 results, to work. The water pump 24 sucks or pumps the coolant and conveys it to the water jacket. Due to the suction and conveying work of the water pump 24 gets the coolant from the water pump 24 circulated at the starting point to clockwise from 1 through the heat sink channel 23 to flow (as from arrows in 1 shown). During the circulation, the temperature of the coolant increases because the coolant absorbs the heat of the engine body 12 absorbed as it flows through the water jacket. The heat of the thus heated coolant is radiated while passing through the heat sink 22 flows.

A bypass channel 25 holding the heatsink 22 bypasses, is with the heat sink channel 23 connected. More precisely, an end (the right end in 1 ) of the bypass channel 25 with a certain point of the heat sink channel 23 between the heat sink 22 and the outlet 10b connected to the water jacket. The other end (the left end in 1 ) of the bypass channel 25 is with a certain point of the heat sink channel 23 between the heat sink 22 and the water pump 24 connected. Thus, the water jacket described above, the heat sink channel 23 , the bypass channel 25 and others together to form a coolant recirculation path.

A flow valve 26 serving as an actuator for controlling the flow rate of the coolant is provided at a merge point at which the above-mentioned other end of the bypass passage 25 with the heat sink channel 23 connected is. The valve opening of the flow valve 26 can be controlled to the flow rate of the coolant passing through the heat sink channel 23 and the bypass channel 25 flows, to steer. In this embodiment, the flow valve 26 designed so that the flow rate of the coolant flowing through the heat sink channel 23 flows, increases as the valve opening becomes larger.

In operation, the flow control valve 26 the flow rate of the coolant in the heat sink channel 23 , whereby the temperature of the coolant, which is the internal combustion engine body 12 cools, is regulated. More specifically, when the flow rate of the cooling means in the heat sink channel 23 increases, the ratio of the coolant, that of the heat sink 22 is cooled to the coolant in the heat sink channel 23 to the engine body 12 flows, thereby increasing the temperature of the coolant for cooling the engine body 12 is lowered. When the flow rate of the coolant in the heat sink channel 23 On the other hand, the ratio of the coolant to that of the heat sink decreases 22 is cooled to the coolant in the coolant Umwälzweg to the engine body 12 flows, lowered, causing the temperature of the coolant to cool the engine body 12 increases.

Various types of sensors for detecting the operating conditions of the vehicle are installed in the vehicle. For example, the heat sink 22 with a heat sink outlet water temperature sensor 27 for measuring the temperature (ie, the radiator outlet water temperature T2) of the coolant that is just the heat sink 22 happened, equipped. The engine body 12 is with an engine exhaust water temperature sensor 28 for measuring the temperature (ie, the engine outlet water temperature To) of the coolant that is just the outlet 10b of the water jacket, as the coolant temperature of the engine body 12 fitted. There is also an accelerator pedal sensor 29 for measuring a displacement of the accelerator pedal 18 by the driver down (or the accelerator pedal position) on the accelerator pedal 18 or installed near it. The throttle body 15 is with a throttle sensor 30 provided for measuring the throttle opening. An inlet pressure sensor 31 For measuring the pressure of the intake air (ie, the intake pressure) is in a portion of the intake passage 13 , the throttle 16 is subordinate, installed. A crank angle sensor 32 is near the crankshaft 19 intended. The crank angle sensor 32 is designed every time the crankshaft 19 rotates by a predetermined range to output a pulse signal. The signal from the crank angle sensor 32 is output, is used to calculate the angle and speed of the crankshaft 19 , that is, the crank angle and the engine speed NE used.

The above ECU 35 is used in the vehicle to corresponding parts of the internal combustion engine 11 on the basis of measured values of the above-mentioned sensors 27 - 32 to control. The ECU 32 has a microcomputer as a main component, and its central processing unit (CPU) executes arithmetic operations according to control programs, initial data, maps and the like stored in a read-only memory (ROM) to various controllers on the basis of the results perform the arithmetic operations. The calculation results obtained from the CPU are stored in advance in a random access memory (RAM).

Now, the operation of the first embodiment constructed as described above will be explained. 2 FIG. 12 is a flowchart showing a control routine as one of the control routines executed by the ECU 35 be performed to the coolant temperature (the engine outlet water temperature To) of the engine body 12 by controlling the opening of the flow valve 16 to regulate. The routine of 2 is performed at appropriate times, for example at predetermined time intervals.

Initially, step S100 is executed to calculate an amount of heat Qw transmitted to the coolant (hereinafter simply referred to as "cooling loss Qw"). This calculation is performed with reference to a map as shown in FIG 3 as an example that defines a relationship between the engine speed NE and the engine load (or engine load factor) and the cooling loss Qw in advance. The load factor is a value that represents the ratio of the actual load to the maximum load of the internal combustion engine 11 stands. The map of 3 is created with respect to each engine outlet water temperature To. As apparent from the map, the cooling loss Qw is relatively small when the engine speed NE is relatively low, and increases as the engine speed NE increases. That's because the amount of heat in the engine body 12 is increased, when the amount of fuel that is supplied to the combustion chamber per unit time increases with increasing combustion engine speed NE, and therefore increases accordingly, the amount of heat from the coolant in the engine body 12 lost, too. A map with egg similar tendency as the map of 3 is used when the engine load factor is used in place of the engine load.

The cooling loss Qw is relatively small when the engine load is relatively small, and increases as the engine load increases. It should be noted, however, that in a region where the engine speed NE is relatively high, the rate of increase of the cooling loss Qw is relatively small as the engine speed NE increases. This is because the fuel supplied to the combustion chamber per unit time becomes more as the engine speed NE increases as described above, and the temperature of the combustion chamber decreases due to the cooling effect resulting from the increase in the amount of fuel Amount of heat from the coolant in the engine body 12 is reduced, is reduced.

The cooling loss Qw depends primarily on the amount of heat in the engine body 12 is produced. In this connection, an element having a reference to the amount of heat generated, for example, a fuel injection amount per combustion cycle, an intake air amount, or the like may be taken as the engine load. The intake air amount is regarded as an element indirectly related to the amount of heat generated because the fuel under the fuel injection control is injected in an amount corresponding to the intake air amount. Apart from the fuel injection amount and the intake air amount, an intake pressure provided from the intake pressure sensor may also be included 31 is measured, a throttle pressure from the throttle sensor 30 is measured or the like taken as an engine load. In this case, however, it is desirable to make corrections as needed.

In step S100, the ECU determines 35 the cooling loss Qw corresponding to the engine speed NE generated by the crank angle sensor 32 is measured, and the engine load on the basis of the map of 3 ,

In step S200, the required radiator flow rate V2 is calculated according to the following expression (1) based on the cooling loss Qw, the target engine outlet water temperature Tt, and the radiator outlet water temperature T2 received from the radiator outlet water temperature sensor 27 is measured, calculated. The required heat sink flow rate V2 is the flow rate of the refrigerant in the heat sink 22 which is required to equalize the engine exhaust water temperature To with the target engine exhaust water temperature Tt. V2 = Qw / {C · (Tt-T2)} (1)

In the above expression (1), C is a coefficient for converting the temperature into the flow rate, which is determined by, for example, a product of the specific heat and density of the refrigerant. The target engine outlet water temperature Tt becomes dependent on the operating state of the engine 11 certainly. For example, when the operating state of the internal combustion engine is in an idling region, the target engine outlet water temperature Tt is set to only a slightly lower temperature (eg, 90 ° C), for example, to avoid or suppress knocking at the start of the vehicle. When the operating state of the internal combustion engine is in a partial load region, the target engine outlet water temperature Tt is set to a relatively high temperature (eg, 100 ° C), for example, to reduce friction loss. When the engine operating condition is in a full load region, the target engine outlet water temperature Tt is set to a relatively low temperature (eg, 80 ° C) to improve the charging effect. It should be noted that the above values of the target engine outlet water temperature Tt are only examples, and that they may be changed if necessary.

Subsequently, in step S300, an opening command value indicative of the flow valve 26 to be sent on the basis of the required radiator flow rate V2 obtained in step S200 and the engine speed NE. This calculation is performed with reference to a map as shown in FIG 4 as an example defining a relationship between the required radiator flow rate V2 and the engine speed NE and the opening command value. In the map of 4 The opening command value decreases as the required radiator flow rate V2 decreases, and increases as the required radiator flow rate V2 increases. In addition, when the engine speed NE is relatively low, the opening command value greatly changes, even if the required radiator flow rate V2 changes only slightly. On the other hand, as the engine speed NE decreases, the rate of change of the opening command value decreases with an increase in the required radiator flow rate V2, that is, the opening command value hardly changes unless the required radiator flow rate V2 changes greatly.

In step S300, the ECU determines 35 the opening command value corresponding to the required radiator flow rate V and the combustion Engine speed NE from the map of 4 ,

In the next step S400, the valve opening is opened by driving the flow valve 26 under a control based on the in step 300 changed specific opening command value. After the operation of step S400 has been completed, the coolant temperature control routine of FIG 2 completed. By controlling the opening of the flow valve 26 is the flow rate of the coolant that is the heat sink 22 is passed, controlled, and the engine outlet water temperature To is substantially equalized to the target engine outlet water temperature Tt.

• (a) In der Steuerung der Öffnung des Strömungsventils 26 schlägt sich die Verbrennungsmotorlast nieder. Daher kann die Verbrennungsmotorauslass-Wassertemperatur To auf die Soll-Verbrennungsmotorauslass-Wassertemperatur Tt, die sich für die aktuelle Verbrennungsmotorlast (d. h. die Verbrennungsmotorlast zur Steuerungszeit) eignet, geregelt werden, anders als in den Fällen, wo die Ventilöffnung nur auf der Basis der Kühlmitteltemperatur gesteuert wird. Wenn das Fahrzeug beispielsweise mit hoher Leistung fährt, wird die Verbrennungsmotorauslass-Wassertemperatur To gesenkt, um die Kühlwirkung jedes Zylinders zu erhöhen. Wenn das Fahrzeug mit einem relativ niedrigen Kraftstoffverbrauch fährt, wird die Verbrennungsmotorauslass-Wassertemperatur To erhöht, um den Wirkungsgrad der Verbrennung in den Zylindern zu erhöhen. Somit kann eine Verbrennungsmotorleistung durch Erfüllen der einander entgegengesetzten Forderungen nach hoher Ausgangsleistung (d. h. Leistung) und niedrigem Kraftstoffverbrauch verbessert werden.
• (b) Der Kühlverlust Qw wird (in Schritt S100) anhand der Verbrennungsmotordrehzahl NE und der Verbrennungsmotorlast als Parameter, welche den Verbrennungsmotorbetriebszustand darstellen, berechnet. Somit kann der Kühlverlust Qw mit hoher Genauigkeit auf der Basis des Verbrennungsmotordrehzahl NE und der Verbrennungsmotorlast, welche den Kühlverlust Qw beeinflussen, berechnet werden. Da der Kühlverlust Qw auf der Basis von sowohl Verbrennungsmotordrehzahl NE als auch Verbrennungsmotorlast berechnet wird, kann die Genauigkeit der Berechnung des Kühlverlusts Qw im Vergleich zu dem Fall, wo die gleiche Größe Qw nur auf der Basis der Verbrennungsmotordrehzahl NE oder der Verbrennungsmotorlast berechnet wird, verbessert werden.
• (c) Der Kühlverlust Qw wird auf der Basis des Betriebszustands des Verbrennungsmotors 11 berechnet (in Schritt S100), und der resultierende Kühlverlust Qw schlägt sich bei der Berechnung der erforderlichen Kühlköper-Strömungsrate V2 (in Schritt S200) nieder. Daher kann auch in dem Fall, dass der Kühlverlust Qw sich mit einer Änderung des Betriebszustands des Verbrennungsmotors 11 ändert, die Öffnung des Strömungsventils 26 gemäß der Änderung des Kühlverlusts Qw gesteuert werden, so dass die Verbrennungsmotorauslass-Wassertemperatur To mit guter Ansprechempfindlichkeit auf die Soll-Verbrennungsmotorauslass-Wassertemperatur Tt gesteuert werden kann. In der oben erörterten bekannten Technik wird die Öffnung des Strömungsventils rückkopplungsweise nur auf der Basis einer Abweichung der Kühlmitteltemperatur von der Kühlmittel-Solltemperatur gesteuert, wodurch es schwierig ist, eine so gute Ansprechempfindlichkeit zu erhalten. Somit kann in der ersten Ausführungsform die Verbrennungsmotorauslass-Wassertemperatur To in relativ kurzer Zeit gesenkt werden, wenn das Fahrzeug in einen Hochleistungs-Fahrzustand gebracht wird, und kann auch in relativ kurzer Zeit erhöht werden, wenn das Fahrzeug in einen Fahrzustand mit niedrigem Kraftstoffverbrauch gebracht wird, wodurch es möglich ist, Verluste, die andernfalls im Hochleistungs-Fahrmodus und im kraftstoffsparenden Fahrmodus auftreten würden, zu verringern.
• (d) Wenn der Öffnungsbefehlswert für das Strömungsventil 26 direkt aus dem Betriebszustand des Verbrennungsmotors 11 oder dergleichen bestimmt wird, und die Öffnung des Strömungsventils 26 entsprechend dem so bestimmten Öffnungsbefehlswert gesteuert wird, muss der Öffnungsbefehlswert erneut bestimmt werden, wenn ein Strömungsventil mit einer anderen Strömungseigenschaft verwendet wird, was die Anwendungsmöglichkeiten des Systems beschränkt. In der ersten Ausführungsform wird dagegen erst einmal die erforderliche Kühlköper-Strömungsrate V2, die der Kühlkörperauslass-Wassertemperatur T2 entspricht, bestimmt, und der Öffnungsbefehlswert für das Strömungsventil 26 wird aus der erforderlichen Kühlköper-Strömungsrate V2 bestimmt. Daher besteht auch in dem Fall, dass ein Strömungsventil mit einer anderen Strömungseigenschaft verwendet wird, keine Notwendigkeit, einen Öffnungsbefehlswert, der der Strömungseigenschaft entspricht, mit Bezug auf jede Art von Strömungsventil zu bestimmen.

The present embodiment described in detail above provides the following advantageous effects.

• (a) In the control of the opening of the flow valve 26 the engine load is reflected. Therefore, the engine outlet water temperature To may be controlled to the target engine outlet water temperature Tt suitable for the current engine load (ie, the engine load at the control time) unlike the cases where the valve opening is controlled based only on the coolant temperature becomes. For example, when the vehicle is running at high power, the engine outlet water temperature To is lowered to increase the cooling effect of each cylinder. When the vehicle is running at a relatively low fuel consumption, the engine outlet water temperature To is increased to increase the combustion efficiency in the cylinders. Thus, engine performance can be improved by meeting the conflicting demands for high output power (ie, power) and low fuel consumption.
• (b) The cooling loss Qw is calculated (in step S100) from the engine rotation speed NE and the engine load as parameters representing the engine operation state. Thus, the cooling loss Qw can be calculated with high accuracy on the basis of the engine speed NE and the engine load, which influence the cooling loss Qw. Since the cooling loss Qw is calculated based on both the engine speed NE and the engine load, the accuracy of calculating the cooling loss Qw can be improved as compared with the case where the same amount Qw is calculated based only on the engine speed NE or the engine load become.
• (c) The cooling loss Qw becomes based on the operating state of the internal combustion engine 11 calculated (in step S100), and the resulting cooling loss Qw is reflected in the calculation of the required radiator flow rate V2 (in step S200). Therefore, even in the case where the cooling loss Qw is a change in the operating state of the internal combustion engine 11 changes, the opening of the flow valve 26 be controlled according to the change of the cooling loss Qw, so that the engine outlet water temperature To can be controlled with good responsiveness to the target engine outlet water temperature Tt. In the prior art discussed above, the opening of the flow valve is feedback controlled only on the basis of a deviation of the coolant temperature from the target coolant temperature, whereby it is difficult to obtain such a good responsiveness. Thus, in the first embodiment, the engine exhaust water temperature To can be lowered in a relatively short time when the vehicle is put in a high-performance running state, and can also be increased in a relatively short time when the vehicle is put in a low-fuel-consumption running state whereby it is possible to reduce losses which would otherwise occur in the high-performance drive mode and in the fuel-saving drive mode.
• (d) When the opening command value for the flow valve 26 directly from the operating state of the internal combustion engine 11 or the like, and the opening of the flow valve 26 is controlled in accordance with the thus-determined opening command value, the opening command value must be determined again when a flow valve having a different flow characteristic is used, which limits the application possibilities of the system. In the first embodiment, on the other hand, first, the required radiator flow rate V2 corresponding to the radiator outlet water temperature T2 is determined, and the opening command value for the flow control valve 26 is determined from the required heat sink flow rate V2. Therefore, even in the case where a flow valve having a different flow characteristic is used, there is no need to determine an opening command value corresponding to the flow characteristic with respect to each type of flow valve.

Second embodiment

Now, a second embodiment of the invention will be described in detail with reference to FIG 5 to 7 described. In the second embodiment, a plurality of heat receiving / radiating circuits are the heat sink 22 bypass, in addition to the bypass channel 25 vorgese hen. With this arrangement, the amount of heat received or radiated in each of the heat receiving / radiating circuits is calculated, and the obtained heat quantity is reflected in the calculation of the required radiator flow rate V2. The second embodiment is different from the first embodiment mainly in this respect. These differences will now be explained in detail.

In the second embodiment, a heating circuit 36 , a throttle body hot water circuit 37 , an EGR cooler cycle 38 , a hydraulic oil heating (transmission oil cooling) circuit 39 for an automatic transmission and a warm air intake circuit 40 provided with hot water heating as heat receiving / radiating circuits, as in 5 shown. The heating circuit 36 is with a heating core (eg a heat exchanger device) 41 connected by the type of hot water heater (heater), and the coolant flowing through the heating circuit 36 flows, is used as a heat source in the heater core 41 fed. The throttle body hot water circuit 37 is with the throttle body 15 connected, and the throttle body 15 is heated while the coolant (warm water) through the hot water circuit 37 flows. Because of the throttle body 15 is heated in this way, the operation of the throttle 16 or the like, for example, stabilized in an extremely cold environment.

Part of the EGR cooler cycle 38 is along an EGR system 42 arranged. The EGR system 42 serves as a means of reducing the nitrogen oxide content in the exhaust gas and functions to expose a portion of the exhaust gas into the intake passage 13 for the purpose of lowering the maximum temperature at which the air / fuel mixture is burned, thereby reducing the amount of nitrogen oxides produced by the internal combustion engine. The EGR system 42 has an EGR channel 43 on, the exhaust duct 21 with the inlet channel 13 combines. The EGR channel 43 is on its downstream side with an EGR chamber 44 provided to return the EGR gas evenly to the respective cylinders. There is also an EGR valve 45 in the EGR channel 43 provided the flow rate of the EGR gas passing through the EGR passage 43 flows, to steer. In this construction, the EGR chamber 44 , the EGR valve 45 and the inlet channel 13 (more precisely, an inlet manifold 46 ) of the coolant flowing through the EGR cooler circuit 38 flows, cooled.

In the present embodiment, the EGR cooler cycle 38 to the downstream end of the throttle body hot water circuit 37 connected. In other words, the circuits 38 . 37 are connected in series. This arrangement may be replaced by another arrangement in which the EGR cooler cycle 38 parallel to the throttle body hot water circuit 37 is provided.

The hydraulic oil heating circuit 39 is with a hydraulic oil heater 47 connected to the automatic transmission. When causes a coolant (warm water) through the hydraulic oil heater 47 flows, the hydraulic oil of the automatic transmission is warmed up during a cold start of the internal combustion engine in a short time, resulting in a reduction of the friction in the automatic transmission. The hydraulic oil heater 47 Also serves as oil cooling when the temperature of the hydraulic oil is high. The warm air intake circuit 40 is with the air scrubber 14 connected. In this design, the intake air is warmed while the coolant passes through a heater core that is close to the air scrubber 14 is provided.

The upstream side portion of each of the heat receiving / radiating circuits described above is at a certain point in the heat sink channel 23 between the outlet 10b of the water jacket and the heat sink 22 connected. Also, the downstream-side portions of these heat-receiving / radiating circuits merge in a merging section 48 , in turn, with the water pump 24 connected is. A union water temperature sensor 49 for measuring the temperature of the coolant in the merging section 48 as merging water temperature T3 is at the merging section 48 the heat receiving / radiating circuits provided. The Unification Water Temperature Sensor 49 is with the ECU 35 connected, as in the case of the other sensors 27 - 32 ,

The structure of the cooling system 20 The second embodiment is different from that of the first embodiment. Hereinafter, a coolant temperature control routine executed by the ECU 35 is executed with reference to the flowchart of 6 described. This coolant temperature control routine differs from that of the first embodiment in terms of an operation with which the required radiator flow rate V2 is calculated. Because the other operations of the routine of 6 are substantially the same as those of the first embodiment, these operations are assigned the same step numbers, and will not be described in detail.

After the ECU 35 In step S100, the cooling loss Qw has been calculated, the ECU calculates 35 the absorbed / radiated heat quantity Qetc, that is, the amount of heat received or radiated in all the heat receiving / radiating circuits is calculated in steps S210-S220. Initially, in step S210, the flow rate of the coolant in the merging section 48 calculated as the union flow rate V3. This calculation will be made with reference to, for example, an in 7 performed map, which is a relationship between the valve opening of the flow valve 26 which defines engine speed NE and the merging flow rate V3. As from the map of 7 As is understood, where the valve opening is in a relatively small range, the merging flow rate V3 is lowered only slightly at a low rate as the valve opening becomes larger. When the valve opening is in a middle or large area, the merging flow rate V3 is substantially constant regardless of the valve opening. Also, the merging flow rate V3 is relatively small when the engine speed NE is relatively low, and increases as the engine speed NE increases. The valve opening used herein may be the opening command value used in the last control cycle.

In the above-described step S210, the ECU determines 35 the merging flow rate V3 corresponding to the valve opening and the engine speed NE, for example, from the map of 7 ,

In the next step S220, the received / radiated heat quantity Qetc in all the heat receiving / radiating circuits is expressed in accordance with the following expression (2) based on the merging flow rate V3 obtained in step S210, the merging water temperature T3 obtained by the uniting water temperature sensor 49 is measured, and the engine outlet water temperature To, from the engine exhaust water temperature sensor 28 is measured, calculated. Qetc = C * V3 * (To - T3) (2)

in the Expression (2) C is a coefficient corresponding to C in the above Expression (1) is the same.

In the next step S230, the required radiator flow rate V2 according to the following expression (1a) is calculated based on the coefficient C, the target engine outlet water temperature Tt, the radiator outlet water temperature T2 received from the radiator outlet water temperature sensor 27 is calculated, the cooling loss Qw and the absorbed / radiated heat quantity Qetc calculated. V2 = (Qw-Qetc) / {C · (Tt-T2)} (1a)

in the above expression (1a), the definitions for C, Tt, T2 and Qw are the same like those of the same parameters, in the above expression (1) were used.

After step (S230) has been executed, steps S300 and S400 corresponding to those of FIG 2 are similar, executed, and the coolant temperature control routine is terminated.

• (e) Mit den verschiedenen Wärme aufnehmenden/abstrahlenden Kreisläufen, die solchermaßen geschaffen werden, wird Wärme aufgenommen oder abgestrahlt (anders ausgedrückt, es findet eine Wärmeein- und -ausstrahlung statt), während das Kühlmittel diese Wärme aufnehmenden/abstrahlenden Kreisläufe passiert. Das Kühlmittel, das der Wärmeein- und -ausstrahlung unterworfen war, strömt durch die Wasserpumpe 24 in den Kühlkörperkanal 23 und passiert wiederum den Wassermantel im Verbrennungsmotorkörper 12. Wenn eine große Wärmemenge in den Wärme aufnehmenden/abstrahlenden Kreisläufen aufgenommen wird, wird die Verbrennungsmotorauslass-Wassertemperatur To mit einer verringerten Geschwindigkeit mit einer verringerten Genauigkeit auf einen Sollwert (d. h. die Soll-Verbrennungsmotorauslass-Wassertemperatur Tt) geregelt, solange die aufgenommene/abgestrahlte Wärmemenge nicht berücksichtigt wird, was zu einem erhöhten Maß an Über- oder Untersteuerung bei der Steuerung der Kühlwassertemperatur führen kann. Die oben genannte Übersteuerung ist ein Phänomen, bei dem die Verbrennungsmotorauslass-Wassertemperatur To nicht bei der Soll-Verbrennungsmotorauslass-Wassertemperatur Tt gehalten werden kann, nachdem die Soll-Verbrennungsmotorauslass-Wassertemperatur Tt erreicht wurde, sondern weiter über den Sollwert Tt hinaus ansteigt. Andererseits ist die oben genannte Untersteuerung ein Phänomen, bei dem die Verbrennungsmotorauslass-Wassertemperatur To nicht bei der Soll-Verbrennungsmotorauslass-Wassertemperatur Tt gehalten werden kann, nachdem sie auf die Soll-Verbrennungsmotorauslass-Wassertemperatur Tt gesenkt wurde, sondern weiter unter den Sollwert Tt sinkt. In dem Fall, wo das Maß der oben beschriebenen Über- oder Untersteuerung wahrscheinlich groß sein wird, muss die Soll-Verbrennungsmotorauslass-Wassertemperatur Tt gesenkt werden, um das normale Funktionieren der entsprechenden Komponenten des Verbrennungsmotorkörpers 12 und anderer angesichts von deren Wärmewiderstand zu gewährleisten. Wenn die Soll-Verbrennungsmotorauslass-Wassertemperatur Tt gesenkt wird, wird jedoch die Verbrennungsmotorauslass-Wassertemperatur To gesenkt, was zu einer erhöhten Reibung im Verbrennungsmotor 11 und im Automatikgetriebe und zu einer verringerten Kraftstoffausnutzung (oder einem erhöhten Kraftstoffverbrauch) führt. In der zweiten Ausführungsform der Erfindung wird die aufgenommene/abgestrahlten Wärmemenge Qetc der Wärme aufnehmenden/abstrahlenden Kreisläufe berechnet, und die so erhaltene Wärmemenge Qetc schlägt sich in der Berechnung der erforderlichen Kühlköper-Strömungsrate V2 nieder. Genauer wird die erforderliche Kühlköper-Strömungsrate V2 gemäß dem oben erhaltenen Ausdruck (1a), der durch Modifizieren des Numerators des oben angegebenen Ausdrucks (1) erhalten wird, berechnet. Demgemäß wird die Verbrennungsmotorauslass-Wassertemperatur To problemlos und schneller mit erhöhter Genauigkeit auf die Soll-Verbrennungsmotorauslass-Wassertemperatur Tt geregelt, auch wenn die aufgenommene/abgestrahlte Wärmemenge der Wärme aufnehmenden/abstrahlenden Kreisläufe sich ändert. Das heißt, das Maß der Über- und der Untersteuerung bei der Steuerung der Kühlmitteltemperatur kann verringert werden, und daher muss die Soll-Verbrennungsmotorauslass-Wassertemperatur Tt im Hinblick auf den Wärmewiderstand der entsprechenden Komponenten des Verbrennungsmotorkörpers 12 und anderer nicht gesenkt werden. Infolgedessen nimmt die Reibung im Verbrennungsmotor 11 und im Automatikgetriebe nicht aufgrund der andernfalls möglichen Senkung der Soll-Verbrennungsmotorauslass-Wassertemperatur Tt zu, und der Kraftstoffverbrauch wird nicht aufgrund der andernfalls möglichen Reibungszunahmen erhöht.
• (f) Im Zusammenhang mit der oben beschriebenen Wirkung (e) sei darauf hingewiesen, dass die aufgenommene/abgestrahlte Wärmemenge Qetc im Wärme aufnehmenden/abstrahlenden Kreislauf relativ klein ist, wenn ein Unterschied zwischen der Wasserzusammenflusstemperatur T3 und der Verbrennungsmotorauslass-Wassertemperatur To klein ist, und dass die aufgenommene/abgestrahlte Wärmemenge Qetc groß ist, wenn der Temperaturunterschied groß ist. Ebenso ist die aufgenommene/abgestrahlte Wärmemenge Qetc klein, wenn die Vereinigungsströmungsrate V3 klein ist, und die aufgenommene/abgestrahlten Wärmemenge Qetc nimmt zu, wenn die Vereinigungsströmungsrate V3 zunimmt.
• In der zweiten Ausführungsform der Erfindung wird die aufgenommene/abgestrahlte Wärmemenge Qetc in allen Wärme aufnehmenden/abstrahlenden Kreisläufen gemäß dem oben angegebenen Ausdruck (2) anhand der Vereinigungsströmungsrate V3, der Vereinigungswassertemperatur T3 und der Verbrennungsmotorauslass-Wassertemperatur To berechnet. Somit wird die aufgenommene/abgestrahlte Wärmemenge mit verbesserter Genauigkeit anhand der Vereinigungsströmungsrate V3, der Vereinigungswassertemperatur T3 und der Verbrennungsmotorauslass-Wassertemperatur To, d. h. anhand von Parametern, welche die aufgenommene/abgestrahlte Wärmemenge Qetc in den oben beschriebenen Wärme aufnehmenden/abstrahlenden Kreisläufen beeinflussen, berechnet.

The second embodiment described in detail above provides the following effects in addition to the effects (a) to (d) described above.

• (e) With the various heat-receiving / radiating circuits thus provided, heat is absorbed or radiated (in other words, there is heat input and emission) as the coolant passes through these heat-receiving / radiating circuits. The coolant that was subjected to the heat input and emission flows through the water pump 24 in the heat sink channel 23 and again passes the water jacket in the engine body 12 , When a large amount of heat is received in the heat receiving / radiating circuits, the engine outlet water temperature To is controlled at a reduced speed with a reduced accuracy to a target value (ie, the target engine outlet water temperature Tt) as long as the absorbed / radiated heat quantity is not is taken into account, which can lead to an increased degree of over- or understeer in the control of the cooling water temperature. The above-mentioned oversteer is a phenomenon in which the engine outlet water temperature To can not be maintained at the target engine outlet water temperature Tt after the target engine outlet water temperature Tt has been reached, but continues to increase beyond the target value Tt. On the other hand, the above-mentioned under-control is a phenomenon in which the engine outlet water temperature To can not be kept at the target engine outlet water temperature Tt after being lowered to the target engine outlet water temperature Tt but continues to fall below the target value Tt. In the case where the extent of the above-described understeer or understeer is likely to be large, the target engine outlet water temperature Tt must be lowered to keep normal operation of the respective components of the engine body 12 and others in view of their thermal resistance. However, when the target engine outlet water temperature Tt is lowered, the engine outlet water temperature To is lowered, resulting in increased friction in the engine 11 and in the automatic transmission, resulting in reduced fuel economy (or increased fuel consumption). In the second embodiment of the invention, the absorbed / radiated heat quantity Qetc of the heat receiving / radiating circuits is calculated, and the heat quantity Qetc thus obtained is reflected in the calculation of the required radiator flow rate V2. More specifically, the required radiator flow rate V2 is calculated according to the above-obtained expression (1a) obtained by modifying the numerator of the above expression (1). Accordingly, the engine outlet water temperature To is smoothly and more quickly controlled to the target engine outlet water temperature Tt with increased accuracy even when the received / radiated heat quantity of the heat receiving / radiating circuits changes. That is, the amount of oversteer and understeer in the control of the coolant temperature can be reduced, and therefore, the target engine outlet water temperature Tt must be in consideration of the thermal resistance of the respective components of the engine body 12 and others are not lowered. As a result, the friction in the internal combustion engine decreases 11 and in the automatic transmission is not due to the otherwise possible lowering of the target engine outlet water temperature Tt, and the fuel consumption is not increased due to the otherwise possible friction increases.
• (f) In the context of the above-described effect (e), it should be noted that the absorbed / radiated heat quantity Qetc in the heat receiving / radiating circuit is relatively small when a difference between the water confluence temperature T3 and the engine outlet water temperature To is small. and that the absorbed / radiated heat quantity Qetc is large when the temperature difference is large. Also, the absorbed / radiated heat quantity Qetc is small when the merging flow rate V3 is small, and the absorbed / radiated heat quantity Qetc increases as the merging flow rate V3 increases.
• In the second embodiment of the invention, the received / radiated heat quantity Qetc in all the heat receiving / radiating circuits is calculated according to the above expression (2) from the merging flow rate V3, the merging water temperature T3 and the engine outlet water temperature To. Thus, the absorbed / radiated heat quantity is calculated with improved accuracy from the merging flow rate V3, the merging water temperature T3, and the engine outlet water temperature To, that is, parameters that influence the absorbed / radiated heat quantity Qetc in the above-described heat receiving / radiating circuits.

Third embodiment

Now, a third embodiment of the invention will be described with reference to FIG 1 and 8th - 10 described. In the third embodiment, a vehicle speed sensor becomes 51 for measuring the vehicle speed SPD as the traveling speed of the vehicle and an ambient temperature sensor 52 for measuring the ambient temperature THA added to the system to detect the operating condition of the vehicle, such as from two-dot chain lines in 1 shown. With the sensors added in this way 51 . 52 is different from the ECU 35 performed processing in the third embodiment of that of the first embodiment.

Hereinafter, a coolant temperature control routine executed by the ECU 35 to be executed with reference to the flowchart of 10 described. The coolant temperature control routine of this embodiment is different from that of the first embodiment in terms of an operation with which the required radiator flow rate V2 is calculated. Because the other operations of the routine of 10 are substantially similar to those of the first embodiment, these operations are assigned the same step numbers and their detailed description is omitted.

After calculating the cooling loss Qw in step S100, the ECU calculates 35 in steps S240-S260, an engine body radiant heat amount Qoeng, which is the amount of heat emitted from the engine body 12 is emitted. Initially, in step S240, the basic engine body radiated heat quantity Qo is referenced to, for example, in 8th 9, which predicts a relationship between the vehicle speed SPD and the basic engine body radiated heat quantity Qo.

It should be noted that the Amount of heat from the engine body 12 is radiated increases when a temperature difference between the temperature of the engine body 12 and the ambient temperature increases. Also, the radiated heat amount increases when an entire surface of high-temperature portions of the engine body 12 increases.

Now it is all the more likely that air with a large temperature difference to the engine body 12 constant around the engine body 12 is around, the higher the traveling speed of the vehicle (the vehicle speed SPD) is. Thus, the amount of heat from the engine body 12 is radiated relatively small when the vehicle speed is relatively low, and increases as the vehicle speed increases.

In view of the above facts, the lower the vehicle speed SPD is, the lower the vehicle body radiated heat amount Qo is set to, and the larger the vehicle speed SPD, the larger the vehicle speed SPD is, as shown in the map of FIG 8th evident. Thus, the ECU determines 35 the basic engine body radiant heat amount Qo, which corresponds to the vehicle speed SPD, which corresponds to the vehicle speed sensor 51 is measured using the map of 8th ,

Subsequently, in step S250, the ambient temperature correction factor Ktha is referenced with reference to, for example, a map which is in FIG 9 and which defines a relationship between the ambient temperature THA and the ambient temperature correction factor Ktha.

As described above, the amount of heat from the engine body 12 is radiated, the higher, the greater a difference between the temperature of the engine body 12 and the ambient temperature is. Therefore, when the ambient temperature THA is low, the difference between the temperature of the engine body decreases 12 and the ambient temperature, resulting in an increase in the amount of radiated heat. On the other hand, when the ambient temperature THA is high, the temperature difference is reduced as described above, resulting in a decrease in the amount of radiated heat.

In view of the above facts, the lower the ambient temperature THA is, the larger the ambient temperature correction factor Ktha is set, and set to a smaller value the higher the ambient temperature THA is, as in FIG 9 shown. Thus, the ECU determines 35 the ambient temperature correction factor Ktha corresponding to the ambient temperature THA detected by the ambient temperature sensor 52 is detected, for example, based on the map of 9 ,

In the next step S270, the required radiator flow rate V2 is calculated according to the following expression (1b) based on the coefficient C, the target engine outlet water temperature Tt, the radiator outlet water temperature T2, the cooling loss Qw, and the engine body radiant heat amount Qoeng. V2 = (Qw-Qoeng) / {C · (Tt-T2)} (1b)

in the Expression (1b) described above are the definitions for C, Tt, T2 and Qw are the same as those of the above-described expression (1).

After execution of step S270, steps S300 and S400 are performed in the same manner as in the flowchart of FIG 2 , and the coolant temperature control routine of 10 will be terminated.

• (g) Es wird angenommen, dass der Kühlverlust Qw des Verbrennungsmotorkörpers 12 sich außer mit der Verbrennungsmotordrehzahl NE und der Verbrennungsmotorlast auch mit der Wärmemenge, die vom Verbrennungsmotorkörper 12 abgestrahlt wird (d. h. der Verbrennungsmotorkörper-Abstrahlwärmemenge Qoeng), ändert. Hierbei wird die Verbrennungsmotorkörper-Abstrahlwärmemenge Qoeng deutlich von der Fahrzeuggeschwindigkeit SPD beeinflusst. Die Verbrennungsmotorkörper-Abstrahlwärmemenge Qoeng wird auch von der Umgebungstemperatur THA beeinflusst, wenn der Grad des Einflusses auch nicht so hoch ist wie der Einfluss der Fahrzeuggeschwindigkeit SPD. Wenn die Einflüsse der Fahrzeuggeschwindigkeit SPD und der Umgebungstemperatur THA groß sind, wird die Verbrennungsmotorauslass-Wassertemperatur To langsam mit verringerter Genauigkeit auf einen Sollwert (d. h. eine Soll-Verbrennungsmotorauslass-Wassertemperatur Tt) geregelt, solange nicht die Verbrennungsmotorkörper-Abstrahlwärmemenge Qoeng berücksichtigt wird, die eine Folge eines erhöhten Grades an Übersteuerung oder Untersteuerung bei der Kühlmitteltemperatursteuerung ist. Um die Zunahme des Grades an Über- oder Untersteuerung zu vermeiden oder zu unterdrücken, kann es notwendig sein, die Soll-Verbrennungsmotorauslass-Wassertemperatur Tt zu senken, um ein normales Funktionieren der entsprechenden Komponenten des Verbrennungsmotorkörpers 12 und anderer im Hinblick auf deren Wärmewiderstand zu gewährleisten. Wenn die Soll-Verbrennungsmotorauslass-Wassertemperatur Tt gesenkt wird, wird jedoch die Verbrennungsmotorauslass-Wassertemperatur To gesenkt, was zu einer erhöhten Reibung im Verbrennungsmotor 11 und im Automatikgetriebe und zu einer verringerten Kraftstoffausnutzung (oder einem erhöhten Kraftstoffverbrauch) führen kann. In der dritten Ausführungsform der Erfindung wird daher die grundsätzliche Verbrennungsmotorkörper-Abstrahlwärmemenge Qo auf der Basis der Fahrzeuggeschwindigkeit SPD bestimmt (in Schritt S240), und der Umgebungstemperatur-Korrekturfaktor Ktha wird auf der Basis der Umgebungstemperatur THA bestimmt (in Schritt S250). Dann wird die Verbrennungsmotorkörper-Abstrahlwärmemenge Qoeng gemäß dem obigen Ausdruck (3) auf der Basis der grundsätzlichen Verbrennungsmotorkörper-Abstrahlwärmemenge Qo und des Umgebungstemperatur-Korrekturfaktors Ktha bestimmt, und die erforderliche Kühlköper-Strömungsrate V2 wird so berechnet (in Schritt S270), dass sich die Verbrennungsmotorkörper-Abstrahlwärmemenge Qoeng darin niederschlägt. Somit wird die Verbrennungsmotorauslass-Wassertemperatur To problemlos schneller und mit besserer Genauigkeit auf die Soll-Verbrennungsmotorauslass-Wassertemperatur Tt geregelt, auch wenn sich die Verbrennungsmotorkörper-Abstrahlwärmemenge Qoeng ändert. Das heißt, das Maß an Über- und Untersteuerung der Kühlmitteltemperatursteuerung kann verringert werden, und daher muss die Soll-Verbrennungsmotorauslass-Wassertemperatur Tt im Hinblick auf den Wärmewiderstand der Komponenten des Verbrennungsmotorkörpers 12 und anderer nicht gesenkt werden. Infolgedessen wird die Reibung des Verbrennungsmotors 11 und des Automatikgetriebes nicht aufgrund der andernfalls möglichen Senkung der Soll-Verbrennungsmotorauslass-Wassertemperatur Tt erhöht, und der Kraftstoffverbrauch wird nicht aufgrund von andernfalls möglichen Reibungszunahmen erhöht.
• (h) Die Verbrennungsmotorkörper-Abstrahlwärmemenge Qoeng wird in den Schritten 240–260 auf der Basis der Fahrzeuggeschwindigkeit SPD und der Umgebungstemperatur THA berechnet. Somit kann die Verbrennungsmotorkörper-Abstrahlwärmemenge Qoeng mit verbesserter Genauigkeit anhand der Fahrzeuggeschwindigkeit SPD und der Umgebungstemperatur THA, von denen angenommen wird, dass sie die Wärmemenge, die vom Verbrennungsmotorkörper 12 abgestrahlt wird, beeinflussen, bestimmt werden. Da die Verbrennungsmotorkörper-Abstrahlwärmemenge Qoeng auf der Basis sowohl der Fahrzeuggeschwindigkeit SPD als auch der Umgebungstemperatur THA berechnet wird, wird auch die Genauigkeit bei der Berechnung im Vergleich zu dem Fall, wo die Verbrennungsmotorkörper-Abstrahlwärmemenge Qoeng nur auf der Basis entweder der Fahrzeuggeschwindigkeit SPD oder der Umgebungstemperatur THA (beispielsweise der Fahrzeuggeschwindigkeit) berechnet wird, verbessert.

The third embodiment described in detail above provides the following effects in addition to the effects (a) to (d) described above.

• (g) It is assumed that the cooling loss Qw of the engine body 12 except with the engine speed NE and the engine load also with the amount of heat from the engine body 12 is radiated (ie, the engine body radiated heat quantity Qoeng) changes. Here, the engine body radiant heat amount Qoeng is significantly influenced by the vehicle speed SPD. The engine body radiant heat amount Qoeng is also affected by the ambient temperature THA when the degree of influence is not as high as the influence of the vehicle speed SPD. When the influences of the vehicle speed SPD and the ambient temperature THA are large, the engine outlet water temperature To is slowly controlled with reduced accuracy to a target value (ie, a target engine outlet water temperature Tt) unless the engine body radiant heat amount Qoeng is considered Result of an increased degree of oversteer or understeer in the coolant temperature control is. In order to avoid or suppress the increase in the degree of oversteer or understeer, it may be necessary to Desired engine outlet water temperature Tt to lower to normal operation of the corresponding components of the engine body 12 and others with regard to their thermal resistance. However, when the target engine outlet water temperature Tt is lowered, the engine outlet water temperature To is lowered, resulting in increased friction in the engine 11 and in the automatic transmission and may result in reduced fuel economy (or increased fuel consumption). In the third embodiment of the invention, therefore, the basic engine body radiated heat amount Qo is determined on the basis of the vehicle speed SPD (in step S240), and the ambient temperature correction factor Ktha is determined on the basis of the ambient temperature THA (in step S250). Then, the engine body radiated heat quantity Qoeng is determined based on the basic engine body radiant heat amount Qo and the ambient temperature correction factor Ktha, and the required radiator flow rate V2 is calculated (at S270) so that the Internal combustion engine radiant heat quantity Qoeng precipitates therein. Thus, even if the engine body radiant heat amount Qoeng changes, the engine outlet water temperature To is smoothly controlled to the target engine outlet water temperature Tt faster and with better accuracy. That is, the amount of over-and under-control of the coolant temperature control can be reduced, and therefore, the target engine outlet water temperature Tt must be in consideration of the thermal resistance of the components of the engine body 12 and others are not lowered. As a result, the friction of the internal combustion engine becomes 11 and the automatic transmission are not increased due to the otherwise possible lowering of the target engine outlet water temperature Tt, and the fuel consumption is not increased due to otherwise possible friction increases.
• (h) The engine body radiant heat amount Qoeng is calculated in steps 240-260 based on the vehicle speed SPD and the ambient temperature THA. Thus, the engine body radiant heat amount Qoeng can be improved with accuracy based on the vehicle speed SPD and the ambient temperature THA assumed to be the amount of heat emitted from the engine body 12 is radiated, influence, determined. Also, since the engine body radiated heat amount Qoeng is calculated on the basis of both the vehicle speed SPD and the ambient temperature THA, the accuracy in the calculation is compared with the case where the engine body radiant heat amount Qoeng is determined based only on either the vehicle speed SPD or Ambient temperature THA (for example, the vehicle speed) is calculated improved.

• (1) Die Kühlmittel-Solltemperatur kann auf eine Weise berechnet werden, die sich von derjenigen der dargestellten Ausführungsformen unterscheidet. Beispielsweise kann die Kühlmittel-Solltemperatur auf der Basis von (a) einer Kombination der grundlegenden Kraftstoffeinspritzmenge und der Verbrennungsmotordrehzahl, (b) einer Kombination der Drosselöffnung und der Kühlmitteltemperatur oder (c) einer Kombination aus dem Einlassdruck und der Kühlmitteltemperatur berechnet werden, wie in der japanischen Patentoffenlegungsschrift Nr. 5-179948 offenbart.
• (2) Die Erfindung kann auf ein Kühlsystem angewendet werden, bei dem die Strömungsrate eines Kühlmittels, das den Kühlkörper passiert, von einer elektrischen Wasserpumpe anstelle einer Wasserpumpe 24, die vom Verbrennungsmotor 11 angesteuert wird, und des Strömungsventils 26, das in den Kühlsystemen der dargestellten Ausführungsformen verwendet wird, gesteuert wird. Als Verfahren zur Steuerung der Öffnung der elektrischen Wasserpumpe kann ein Öffnungsbefehlswert direkt beispielsweise auf der Basis des Betriebszustands des Verbrennungsmotors 11 bestimmt werden, und die Öffnung der Wasserpumpe kann entsprechend dem Öffnungsbefehlswert gesteuert werden. In diesem Fall kann jedoch der Öffnungsbefehlswert nicht bestimmt werden, solange nicht eine Strömungseigenschaft der elektrischen Wasserpumpe spezifiziert wurde. In der modifizierten Ausführungsform (2) wird die erforderliche Kühlköper-Strömungsrate V2, die der Kühlkörperauslass-Wassertemperatur T2 entspricht, bestimmt, und der Öffnungsbefehlswert der elektrischen Wasserpumpe wird anhand der erforderlichen Kühlköper-Strömungsrate V2 auf die gleiche Weise bestimmt wie in den dargestellten Ausführungsformen. Auf diese Weise kann der Öffnungsbefehlswert anhand der erforderlichen Kühlköper-Strömungsrate V2 auch dann erhalten werden, wenn die Strömungseigenschaft nicht spezifiziert wurde.
• (3) In der ersten Ausführungsform kann der Kühlverlust Qw auf der Basis nur entweder der Verbrennungsmotordrehzahl NE oder der Verbrennungsmotorlast (oder des Verbrennungsmotorlastfaktors) bestimmt werden.
• (4) In der dritten Ausführungsform kann die Verbrennungsmotorkörper-Abstrahlwärmemenge Qoeng auf der Basis nur entweder der Fahrzeuggeschwindigkeit SPD oder der Umgebungstemperatur THA bestimmt werden. Beispielsweise kann die grundsätzliche Verbrennungsmotorkörper-Abstrahlwärmemenge Qo unverändert als Verbrennungsmotorkörper-Abstrahlwärmemenge Qoeng verwendet werden, ohne dass sie mit dem Umgebungstemperatur-Korrekturfaktor Ktha multipliziert werden müsste.
• (5) Die zweite Ausführungsform und die dritte Ausführungsform der Erfindung können miteinander kombiniert werden. Das heißt, die aufgenommene/abgestrahlte Wärmemenge Qetc und die Verbrennungsmotorkörper-Abstrahlwärmemenge Qoeng können sich in der Berechnung der erforderlichen Kühlköper-Strömungsrate V2 niederschlagen. Genauer kann die erforderliche Kühlköper-Strömungsrate V2 gemäß dem folgenden Ausdruck (1c) berechnet werden. V2 = (Qw – Qetc – Qoeng)/{C·(Tt – T2)} (1a) Auf diese Weise wird die Verbrennungsmotorauslass-Wassertemperatur To noch problemloser mit verbesserter Genauigkeit auf die Soll-Verbrennungsmotorauslass-Wassertemperatur Tt gesteuert, auch wenn die aufgenommene/abgestrahlte Wärmemenge Qetc der Wärme aufnehmenden/abstrahlenden Kreisläufe und die Verbrennungsmotorkörper-Abstrahlwärmemenge Qoeng sich ändern. Infolgedessen kann der Grad der Über- oder Untersteuerung der Kühlmitteltemperatur verringert werden, und die andernfalls mögliche Verschlechterung der Kraftstoffausnutzung kann noch weiter unterdrückt werden.
• (6) Betreffend einen oder mehrere der Wärme aufnehmenden/abstrahlenden Kreisläufe der zweiten Ausführungsform, die eine besonders große Wärmemenge aufnehmen oder abstrahlen, beispielsweise den Heizkreislauf 36, den Hydrauliköl-Heizkreislauf 39 und den Warmluftansaug-Kreislauf 40 betreffend, kann die aufgenommene/abgestrahlte Wärmemenge auf die nachstehend beschriebene Weise gemessen oder korrigiert werden, ohne den Vereinigungswassertemperatursensor 49 zu verwenden. Betreffend beispielsweise den Heizkreislauf 36 wird die Windgeschwindigkeit in der Nähe des Heizkerns 41 gemessen, während das Fahrzeug fährt, und die Temperaturen werden an den stromaufwärtigen und stromabwärtigen Seiten des Heizkerns 41 gemessen. Dann wird die Wärmemenge, die vom Heizkern 41 abgestrahlt wird, anhand eines Unterschieds zwischen der stromaufwärtsseitigen Temperatur und der stromabwärtsseitigen Temperatur des Heizkerns 41 und der Windgeschwindigkeit gemessen. Betreffend den Hydrauliköl-Heizkreislauf 39 wird die grundlegende abgestrahlte Wärmemenge anhand eines Unterschieds zwischen der Temperatur eines Kühlmittels, das durch den Kreislauf 39 strömt, und der Temperatur des Hydrauliköls bestimmt. Dann wird die Wärmemenge, die vom Hydrauliköl-Heizkreislauf 39 aufgenommen oder abgestrahlt wird, durch Multiplizieren der grundlegenden abgestrahlten Wärmemenge mit einem Korrekturfaktor berechnet, der von der Strömungsrate des Kühlmittels abhängt, das die Hydraulikölheizung 47 passiert. Betreffend den Warmluftansaug-Kreislauf 40 wird die abgestrahlte Wärmemenge auf der Basis der Temperaturen auf der stromaufwärtigen und der stromabwärtigen Seite des Heizkerns, der sich in der Nähe des Luftwäschers 14 befindet, und der Menge der angesaugten Luft, die durch den Einlasskanal 13 strömt, berechnet. Anschließend wird die Wärmemenge Qetc durch Addieren der wie oben ermittelten aufgenommenen/abgestrahlten Wärmemengen ermittelt und wird im oben angegebenen Ausdruck (1a) verwendet, um die erforderliche Kühlköper-Strömungsrate V2 zu berechnen.
• (7) In der dritten Ausführungsform kann die Temperatur der angesaugten Luft als Ersatzwert für die Umgebungstemperatur THA, die vom Umgebungstemperatursensor 52 gemessen wird, verwendet werden.

Although the first, second and third embodiments of the invention have been described above, the invention may be practiced otherwise, as in the following examples.

• (1) The target coolant temperature may be calculated in a manner different from that of the illustrated embodiments. For example, the desired coolant temperature may be calculated based on (a) a combination of the basic fuel injection amount and the engine speed, (b) a combination of the throttle opening and the coolant temperature, or (c) a combination of the intake pressure and the coolant temperature, as shown in FIG Japanese Patent Laid-Open Publication No. 5-179948 disclosed.
• (2) The invention can be applied to a refrigeration system in which the flow rate of a refrigerant passing through the heat sink is from an electric water pump instead of a water pump 24 by the combustion engine 11 is controlled, and the flow valve 26 controlled in the cooling systems of the illustrated embodiments. As a method of controlling the opening of the electric water pump, an opening command value may be directly based on, for example, the operating state of the internal combustion engine 11 can be determined, and the opening of the water pump can be controlled according to the opening command value. In this case, however, the opening command value can not be determined unless a flow characteristic of the electric water pump has been specified. In the modified embodiment (2), the required radiator flow rate V2 corresponding to the radiator outlet water temperature T2 is determined, and the opening instruction value of the electric water pump is determined based on the required radiator flow rate V2 in the same manner as in the illustrated embodiments. In this way, the opening command value can be obtained from the required radiator flow rate V2 even if the flow characteristic was not specified.
• (3) In the first embodiment, the cooling loss Qw may be determined on the basis of only either the engine speed NE or the engine load (or engine load factor).
• (4) In the third embodiment, the engine body radiated heat quantity Qoeng can be determined on the basis of only either the vehicle speed SPD or the ambient temperature THA. For example, the basic engine body radiant heat amount Qo may be used as the engine body radiant heat amount Qoeng without having to be multiplied by the ambient temperature correction factor Ktha.
• (5) The second embodiment and the third embodiment of the invention can be combined with each other. That is, the absorbed / radiated heat quantity Qetc and the engine body radiant heat amount Qoeng may be reflected in the calculation of the required radiator flow rate V2. More specifically, the required radiator flow rate V2 can be calculated according to the following expression (1c). V2 = (Qw - Qetc - Qoeng) / {C · (Tt - T2)} (1a) In this way, even if the received / radiated heat quantity Qetc of the heat receiving / radiating circuits and the engine body radiant heat amount Qoeng change, the engine outlet water temperature To is controlled to the target engine outlet water temperature Tt even more smoothly with improved accuracy. As a result, the degree of over or under control of the coolant temperature can be reduced, and the otherwise possible deterioration of the fuel efficiency can be further suppressed.
• (6) Concerning one or more of the heat receiving / radiating circuits of the second embodiment, which receive or radiate a particularly large amount of heat, for example, the heating circuit 36 , the hydraulic oil heating circuit 39 and the warm air intake circuit 40 2, the received / radiated heat amount can be measured or corrected in the manner described below without the merging water temperature sensor 49 to use. Concerning, for example, the heating circuit 36 The wind speed is near the heater core 41 measured while the vehicle is running, and the temperatures are at the upstream and downstream sides of the heater core 41 measured. Then the amount of heat from the heater core 41 is radiated by a difference between the upstream-side temperature and the downstream-side temperature of the heater core 41 and the wind speed measured. Regarding the hydraulic oil heating circuit 39 The basic amount of radiated heat is determined by a difference between the temperature of a coolant flowing through the circuit 39 flows, and determines the temperature of the hydraulic oil. Then the amount of heat from the hydraulic oil heating circuit 39 is calculated or multiplied by multiplying the basic radiated heat amount by a correction factor that depends on the flow rate of the coolant that controls the hydraulic oil heater 47 happens. Regarding the warm air intake circuit 40 the amount of radiated heat will be based on the temperatures on the upstream and downstream sides of the heater core, which are close to the air scrubber 14 is located, and the amount of air sucked in through the inlet duct 13 flows, calculated. Subsequently, the amount of heat Qetc is determined by adding the absorbed / radiated heat quantities as determined above and used in the above expression (1a) to calculate the required radiator flow rate V2.
• (7) In the third embodiment, the temperature of the intake air may be substituted for the ambient temperature THA obtained from the ambient temperature sensor 52 is used.

Claims (16)

Cooling system ( 20 ) for an internal combustion engine ( 11 ), which has a radiator grille ( 22 ) provided in a coolant circulation path of the internal combustion engine, and an actuator ( 26 ), which controls a flow rate of a coolant flowing through the grille, wherein the actuator is controlled such that a coolant temperature of the internal combustion engine becomes largely equal to a coolant target temperature, characterized in that it comprises: 35 ) for calculating a coolant loss as an amount of heat discharged from the engine and absorbed by the coolant based on an operating condition of the engine, and a required grille flow rate based on the cooling loss, the target coolant temperature, and a coolant temperature the grille flow rate is calculated, wherein the required grille flow rate is a quantity of refrigerant that must flow through the grille to approximately approach the coolant temperature of the desired coolant temperature; and a control means ( 35 ) for controlling the actuator based on the required grille flow rate obtained by the calculating means. A cooling system according to claim 1, wherein the calculating means further comprises a received / radiated heat quantity of at least one heat receiving / radiating circuit ( 36 . 37 . 38 . 39 . 40 ) calculated in the coolant recirculation path bypassing the radiator grille, and calculating the required radiator grille flow rate on the basis of the received / radiated heat amount, the cooling loss, the target coolant temperature, and the temperature of the coolant that has passed through the radiator grille , cooling system according to claim 2, wherein the at least one heat receiving / radiating circuit a lot of heat includes receiving / radiating circuits, and wherein the Calculation means the absorbed / radiated heat quantity the heat receiving / radiating circuits based on a combined Flow rate those at a portion that absorbs / radiates the heat cycles is measured, a combined coolant temperature, measured at the common section and the coolant temperature of the internal combustion engine. cooling system according to claim 3, wherein said calculating means is the combined flow rate based on a current opening the actuator and an operating condition of the internal combustion engine calculated. cooling system according to claim 1 or claim 2, wherein the calculating means further a quantity of heat, that of a main body the internal combustion engine is radiated, calculated and the required Radiator flow rate based on the amount of heat that of the engine body is emitted, the loss of cooling, the coolant set temperature and the temperature of the coolant, the grille flows through has, calculated. cooling system according to claim 5, wherein the internal combustion engine is installed in a vehicle and the calculating means is the amount of heat radiated from the engine body is based on a vehicle speed and / or an ambient temperature around the vehicle. cooling system according to one of the claims 1-6, where the operating state of the internal combustion engine used to calculate the cooling loss is used, a speed of the internal combustion engine and / or a Combustion engine load includes. cooling system according to one of the claims 1-7, where the calculating means has an opening command the base of the required grille flow rate, which is obtained from the calculation means, and the operating condition of the internal combustion engine and an opening of the actuator according to the opening command controls. Method for controlling a cooling system ( 20 ) for an internal combustion engine ( 11 ), which has a radiator grille ( 22 ) provided in a coolant circulation path of the internal combustion engine, and an actuator ( 26 ), which controls a flow rate of a coolant flowing through the grille, wherein the actuator is controlled so that a coolant temperature of the internal combustion engine becomes largely equal to a target coolant temperature, characterized by comprising the steps of: calculating a coolant loss as an amount of heat discharged from the engine and taken in by the coolant based on an operating state of the engine, and calculating a required grille flow rate based on the cooling loss, the target coolant temperature, and a temperature of the coolant that has passed through the grille; wherein the required grille flow rate is a quantity of refrigerant that must flow through the grille to substantially approximate the coolant temperature to the desired coolant temperature; and controlling the actuator based on the required grille flow rate. The method of claim 9, further comprising the steps of: calculating a received / radiated heat quantity of at least one heat receiving / radiating circuit ( 36 . 37 . 38 . 39 . 40 ) provided in the refrigerant circulation path bypassing the grille, and calculating the required grille flow rate on the basis of the received / radiated heat amount, the cooling loss, the target coolant temperature, and the temperature of the coolant that has passed through the grille. The method of claim 10, wherein the at least a heat receiving / radiating circuit a variety of heat receiving / radiating cycles and wherein the amount of heat absorbed / radiated the heat receiving / radiating circuits based on a combined Flow rate those at a portion that absorbs / radiates the heat cycles is measured, a combined coolant temperature, measured at the common section and the coolant temperature of the internal combustion engine is calculated. The method of claim 11, wherein the combined flow rate based on a current opening the actuator and the operating condition of the internal combustion engine is calculated. The method of claim 9 or claim 10, which further comprising the following steps: Calculating a quantity of heat, that of a main body the internal combustion engine is radiated; and Calculate the required grille flow rate based on the amount of heat that of the engine body is emitted, the loss of cooling, the coolant set temperature and the temperature of the coolant, through the radiator grille streamed is. The method of claim 13, wherein the internal combustion engine is installed in a vehicle and the amount of heat emitted by the engine body is based on a vehicle speed and / or an ambient temperature around the vehicle is calculated. Method according to one of claims 9-14, wherein the operating state the internal combustion engine used to calculate the cooling loss a speed of the internal combustion engine and / or an engine load includes. The method of any of claims 9-15, further comprising the following Steps: Calculating an opening command on the basis the required grille flow rate and the operating state of the internal combustion engine; and Taxes an opening the actuator according to the opening command.